Percutaneous transluminal angioplasty (PTA), defined as any percutaneous transluminal:. method of decreasing stenosis within a blood vessel, whether caused by the existence of an atheromatous plaque, thrombosis, embolus, and/or mineral deposit, by any of a number of means such as balloon dilatation, thermal ablation, laser atherectomy, mechanical shaving, extraction, or ultrasonic pulverization, hereinafter referred to as angioplasty, is widely used in the treatment of occlusive vascular disease. However, it has been found that restenosis frequently occurs, and in the case of coronary angioplasty, restenosis occurs in about a third of cases within 6 months of the procedure.
European Patent Application 0219782 to Scholkens (Hoechst) discloses the treatment of atherosclerosis, thrombosis and/or peripheral vascular disease in mammals using an angiotensin converting enzyme (ACE) inhibitor or its physiologically tolerable salts. It further discloses that because ACE is predominantly localized in the luminal plasma membrane of the endothelial cell, ACE inhibitors can interfere in platelet-endothelium interaction. In addition, Scholkens discloses that ACE inhibition potentiates the action of bradykinin (a strong stimulator of prostacyclin release from endothelial cells) by inhibiting its degradation and ACE inhibitors, consequently, have an inhibitory effect on platelet aggregation.
Powell, J. S. et al., "Inhibitors of Angiotension-Converting Enzyme Prevent Myointimal Proliferation After Vascular Injury," Science, Vol. 245,186-188 Jul. 14, 1989, disclose that angiotyensin-converting enzyme may participate in modulating the proliferative response of the vascular wall after arterial injury, and inhibition of this enzyme may have therapeutic applications to prevent the proliferative lesions that occur after coronary angioplasty and vascular surgery.
Other references which indicate that ACE inhibitors may prevent restenosis following angioplasty include "AII is Mitogenic for Endothelial Cells" (Clin. Res., 36, 1988:259A); "Exposure of Smooth Muscle Cells to AII Results in Expression of the Proto-Oncogene for PDGF" (J. Clin. Invest., 83, 1989:1419); "Cilazapril (and Captopril) Reduces the Myointimal Proliferation (Restenosis) in Rat Carotids Subjected to Balloon Angioplasty" (Clin. Res., 37, 1989:286A).
U.S. Pat. No. 4,337,201 to Petrillo discloses phosphinylalkanoyl substituted prolines, including fosinopril, which are ACE inhibitors useful for treating hypertension.
U.S. Pat. No. 4,374,829 discloses carboxyalkyl dipeptide derivatives, including enalapril, which are ACE inhibitors useful for treating hypertension.
U.S. Pat. No. 4,452,790 to Karanewsky et al. discloses phosphonate substituted amino or imino acids and salts thereof and covers (S)-1-[6-amino-2-[[hydroxy(4-phenylbutyl)phosphinyl]-oxy]-1-oxohexyl]-L-pr oline (SQ 29,852, ceranapril). These compounds are ACE inhibitors useful in treating hypertension.